Amsterdam will celebrate its 750th anniversary as a city in 2025, with festivities planned throughout the year. One of the birthday gifts to the city is a forest of 750 large and 7,500 small trees, which will first spend a day on the A10 ring road during the birthday festival. Here, visitors will learn about the trees and their added value for the city, and attention will be drawn to the importance of more greenery.

The initiators of this special gift, Stichting De Gezonde Stad (The Healthy City Foundation), landscape artist Bruno Doedens and the Municipality of Amsterdam, want to use this project to promote more greenery in and around Amsterdam. The aim of this project is to demonstrate the added value of large green spaces.

Forest on the A10 ring road brings visitors face to face with the facts
Placing trees in containers on the motorway during the summer festival immediately highlights the added value of greenery. People are instantly more aware of the positive contribution trees make to their well-being. For example, heat measurements were taken on the asphalt between the trees to demonstrate the cooling effect. The day on the A10 motorway was a sweltering summer's day, with the only cool spot on the asphalt being between the trees. During the crowded festival, the Forest on the Ring is primarily a place for rest, meeting people and inspiration, encouraging people to consider the role that nature and trees actually play in their lives and living environment.

Fruit crates become tree planters
In order to be able to move the trees in the summer, they were planted in tree planters in the winter, which were specially prepared for this event. These tree planters are wooden fruit crates that can be reused in the fruit industry afterwards. The modifications were made in such a way that they can be easily reversed. For example, they are lined with a layer of coconut fibre to prevent the substrate from escaping. An anchoring system was also installed to ensure that the tree stands firmly in the container. This meant that the wind load and the tilted transport to the festival site did not pose any problems. A plastic layer with sturdy loops was also installed, which will ensure that the container can be dismantled and the substrate removed quickly in the autumn.

Due to the very limited growth period of three months from planting to transport, care and cultivation were intensive. Nothing could go wrong and there was no time to rectify any mistakes. For example, the load-bearing capacity of the wooden tree containers is limited and there were also weight restrictions on transport. That is why the substrate in which the trees were planted was made specifically for the job, lightweight, with a good permeable structure and good capillary action to retain moisture. During cultivation, organic root stimulants were also used to promote root formation, such as compost tea and a mycorrhiza preparation.

Destination Amsterdam - A10 ring road
The 750 tree containers were placed at an angle on trailers using box tippers so that the trees, some of which were up to nine metres long, could be transported across the motorway without any problems. There were also height restrictions due to the viaducts along the route and in the city because of the overhead lines of the tram tracks.

Once ready for transport, the trees were regularly sprayed and misted to prevent the crowns from overheating. Because each tree was equipped with a GPS tracker, the trees could be tracked live on their way to the city, and their current location can be pinpointed on the Open Tree Map Amsterdam. A total of 62 trailers with trees were lined up at the Olympic Stadium. Upon arrival in the city, many residents came to take photos of the trees, as many found them so unique. Trailer after trailer was pulled to the A10 motorway during the night. There, a team unloaded each tree container from the trailer and placed it in the right spot on the motorway. The festival took place during the day, and the following night, all the trees were loaded back onto the trailers.

After the event, the trees were placed at “the tree campsite”, Riekerpark in Amsterdam. There, the trees are cared for until they shed their leaves and go into winter dormancy (November – April). All trees have been assigned a location in and around the municipality of Amsterdam in advance, where they will be permanently planted and can contribute to the city's green ambitions.